Document and improve API for unmountIfNoConsumers

Author: vadikoom

README.md

@@ -297,6 +297,19 @@ const App = () => {
 
 ```     
 
+### Unmounting hooks when there are no consumers
+
+You can pass the last optional parameter `options` to the `singletonHook` to 
+configure if the hook should be unmounted when no one consumes it:
+```js
+
+const useHook = singletonHook(
+  initVal,
+  () => { /*hook body*/ }, 
+  { unmountIfNoConsumers: true }
+);
+```
+
 ## React Native
 To use this library with react-native you always have to mount `SingletonHooksContainer` manually. 
 See how to do it in example: *use react-redux (or any other context) inside singletonHook*

index.d.ts

@@ -3,6 +3,13 @@ export = ReactSingletonHook;
 export as namespace ReactSingletonHook;
 
 declare namespace ReactSingletonHook {
-  function singletonHook<ValueType>(initialState: ValueType | (() => ValueType), useHook: () => ValueType): () => ValueType;
+  function singletonHook<ValueType>(
+      initialState: ValueType | (() => ValueType),
+      useHook: () => ValueType,
+      options?: {
+        unmountIfNoConsumers?: boolean
+      }
+  ): () => ValueType;
+
   function SingletonHooksContainer(): any;
 }

src/components/SingletonHooksContainer.js

@@ -11,7 +11,7 @@ let mountQueue = [];
 const mountIntoContainerDefault = (item) => {
   mountQueue.push(item);
   return () => {
-    throw new Error('damn');
+    throw new Error('Can not unmount container! It is like a bug in react-singleton-hook library, because of unmountIfNoConsumers: true');
     // mountQueue = mountQueue.filter(i => i !== item);
   };
 };

src/singletonHook.js

@@ -2,12 +2,15 @@ import { useEffect, useState } from 'react';
 import { addHook } from './components/SingletonHooksContainer';
 import { batch } from './utils/env';
 
-export const singletonHook = (initValue, useHookBody, unmountIfNoConsumers = false) => {
+export const singletonHook = (initValue, useHookBody, options = {}) => {
   let mounted = false;
   let removeHook = undefined;
   let initStateCalculated = false;
   let lastKnownState = undefined;
   let consumers = [];
+  let {
+    unmountIfNoConsumers = false
+  } = options;
 
   const applyStateChange = (newState) => {
     lastKnownState = newState;

test/integration/integration.spec.js

@@ -112,7 +112,7 @@ describe('singletonHook', () => {
   it('unmounts hook if no consumers', () => {
     const unmountCallback = jest.fn();
     const initVal = 'initVal';
-    const useHook = singletonHook(initVal, () => useEffect(() => unmountCallback), true);
+    const useHook = singletonHook(initVal, () => useEffect(() => unmountCallback), { unmountIfNoConsumers: true });
 
     const Tmp = () => {
       useHook();

test/react-native/native.spec.js

@@ -101,7 +101,7 @@ describe('singletonHook', () => {
   it('unmounts hook if no consumers', () => {
     const unmountCallback = jest.fn();
     const initVal = 'initVal';
-    const useHook = singletonHook(initVal, () => useEffect(() => unmountCallback), true);
+    const useHook = singletonHook(initVal, () => useEffect(() => unmountCallback), { unmountIfNoConsumers: true });
 
     const Tmp = () => {
       useHook();